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Where does reality end and digital space begin? Projection mapping shifts the bounds of visual expression and perception.
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Now THIS Is a Synapse
by Virginia Hughes
Every time I read about the synapse, the all-important junction between two neurons, the cartoon above pops into my head. It shows the gist of how a synapse works: An electrical pulse enters the cell on the left and activates those little blue balls, called vesicles, to release their chemical contents, called neurotransmitters. The neurotransmitters spill out into the space between the cells, called the cleft, and activate those blue rectangles, called ion channels. The channels trigger the cell on the right to fire its own electrical pulse, or action potential, and this message travels on to the next cell. It’s pretty neat. Our brains are full of trillions of synapses, each with the capability of converting an electrical signal into a chemical one and back again.
My doodle is conceptually useful for understanding many neuroscience studies. It helped me visualize, for example, how researchers record the messages of brain cells, and how the synapse plays a role in developmental disorders, and how the firing patterns of all of these synapses provide our brains with a sophisticated coding scheme.
The downside of the cartoon synapse is that it gives a false impression. It makes it seem as if the synapse is simple and all figured out, when actually it’s mostly baffling. I was reminded of its complexity by a study published in today’s issue of Science. Researchers in Germany used an array of techniques — including Western blot, mass spectrometry, electron microscopy, and super-resolution fluorescence microscopy — to create a three-dimensional model of a typical synapse in the adult rat brain. You’ll see in the video below that their new model doesn’t look much like my drawing:
synapse video from Virginia Hughes on Vimeo.
To get the most out of the video, click on the white arrows in the lower right hand corner, which will expand it to full screen. The video shows the synaptic bouton, which is the left part of my cartoon. The glowing red “active zone” at the bottom is where the neurotransmitters get dumped into the cleft. Toward the end of the video you can see a close-up of a vesicle releasing its contents and then being recycled by the cell.
The model shows some 300,000 individual proteins, and remember — they’re all hanging out at a single synapse! The image below shows a cross-section of the bouton; each color corresponds to a different kind of protein. The active zone is again the glowing red part at the bottom.
Wilhelm et al., Science 2014 (Click to enlarge)
More often than not, neuroscientists (and therefore, science writers covering neuroscience) tend to focus on a single protein at a time. For instance, I’ve written about that green guy, parvalbumin, because in certain neurons the protein seems to trigger high-frequency brain waves that have been linked to cognition. And that red SNAP-25 has been linked to ADHD, and the yellow VDAC has been proposed as a good target for chemotherapy drugs.
The only way to untangle this complex picture is to focus on its individual components, figuring out one piece at a time. But the next time you read about one of those pieces, recall how it fits into the whole, and be wowed.
What a build-up: Tom Waits has spent the past week dropping hints about an announcement he had planned for today, and the Web was thick with speculation: Could it be a tour? New music? A concert cruise? Nope. Turns out it was the release of a new video for "Hell Broke Luce," a scabrous, blackly comic anti-war song from last year's Bad As Me. The clip was the source of various surreal images posted on Waits' website last week, depicting the singer sporting an eyepatch and a scimitar, underwater flanked by boxy sharks (that turn out to be submarines) and poking an oversized spoon at a roaring fire.
Directed by Matt Mahurin, the video is as gritty as the song, as Waits pulls a small house through an arid, blasted landscape; over the ocean while surrounded by warring flotillas; and under water, trailed by boxy shark submarines.
Waits addressed the speculation over his clues in a statement: "As most of you guessed, it’s a tour . . . a tour de force!" The singer said he and Kathleen Brennan, his wife and songwriting partner, envisioned the song as "an enlightened drill sergeant yelling the hard truths of war to a brand new batch of recruits. The video grew from the gnawing image of a soldier pulling his home, through a battlefield, at the end of a rope. I think you will agree, it's uplifting and fun."
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